NEW YORK, March 6. /TASS/. The United States has frozen assets of two Russian banks worth some $637 million, US media reported Thursday.

"Banks controlled by three billionaire friends of Russian President Vladimir Putin have seen about $640 million of assets frozen in the US" over the situation in Ukraine, the Wall Street Journal reported.

"Hit the hardest is Bank Rossiya, which had at least $572 million blocked in US accounts, according to records released to The Wall Street Journal by the Treasury Department. That is equivalent to roughly 10% of its 2013 assets, at today’s exchange rate," the article said.

"Also hit is SMP Bank, majority-owned by Arkady and Boris Rotenberg… Their bank has had at least $65 million - equal to about 2% of 2013 assets - blocked across dozens of accounts in US financial institutions, Treasury documents show," it said.

Both banks are on the list of Russian enterprises and financial institutions the US imposed economic sanctions on. The list also includes Russian state-controlled energy giant Gazprom, Gazprom Neft, Lukoil, Surgutneftegaz and Rosneft.

The punitive measures are also in place against Russia’s largest lender Sberbank, the Bank of Moscow, Gazprombank, Rosselkhozbank, Vnesheconombank, VTB and a number of defense industry enterprises.

Russian officials and companies came under the first batch of Western sanctions, including visa bans and asset freezes, after Russia incorporated Crimea in mid-March 2014 after the February 2014 coup in Ukraine.

Despite Moscow’s repeated statements that the Crimean referendum on secession from Ukraine was in line with the international law and the UN Charter and in conformity with the precedent set by Kosovo’s secession from Serbia in 2008, the West and Kiev have refused to recognize the legality of Crimea’s reunification with Russia.

The West announced new, sectoral, restrictions against Russia in late July 2014, in particular, for what the West claimed was Moscow’s alleged involvement in protests in Ukraine’s southeast.

In response, Russia imposed on August 6, 2014 a one-year ban on imports of beef, pork, poultry, fish, cheeses, fruit, vegetables and dairy products from Australia, Canada, the European Union, the United States and Norway.

New large-scale punitive measures against Russia followed in September and December 2014.

Russia has constantly dismissed accusations of "annexing" Crimea claiming Crimea reunified with Russia voluntarily after a referendum. Allegations that Moscow could in any way be involved in hostilities in east Ukraine have been dismissed as well.